International Journal of Research in Nursing Original Research Paper Nitrogen Narcosis in Hyperbaric Chamber Nurses 1,2 Denise F. Blake, 3Derelle A. Young and 4Lawrence H. Brown 1Emergency Department, The Townsville Hospital, Douglas, Queensland, Australia 2School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, 4814, Australia 3Hyperbaric Medicine Unit, The Townsville Hospital, Townsville, Queensland, Australia 4Mount Isa Centre for Rural and Remote Health, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Townsville, QLD, 4814, Australia Article history Abstract: Hyperbaric nursing has become a specialty requiring high skill Received: 24-09-2014 and knowledge. Nitrogen narcosis is a perceived risk for all inside Revised: 03-10-2014 hyperbaric chamber nurses. The actual degree of impairment at pressure Accepted: 16-12-2015 has not been quantified. Twenty eight subjects participated in the study. Sixteen hyperbaric nurse candidates and five experienced hyperbaric Corresponding Author: Denise F. Blake, nurses completed Trail Making Test A (TMTA) pre and post compression Emergency Department, and at 180 kPa and 300 kPa. Seven experienced hyperbaric staff acted as The Townsville Hospital, an unpressurized reference. Time to completion of the test was recorded in Douglas, Queensland, Australia seconds; pre-test anxiety and perceived symptoms of narcosis at 300 kPa Email: [email protected] were also recorded. There were no statistically significant differences in the corrected TMT A times at the four different time periods. There was a trend to poorer performance by the nurse candidates at 180 kPa however this was not statistically significant. Most subjects felt some degree of narcosis at 300 kPa. Most hyperbaric chamber nurses can overcome the effects of nitrogen narcosis at 180 and 300 kPa to maintain or improve performance in the TMT A. Poor performance by hyperbaric nurse candidates maybe due to individual susceptibility or lack of ability to compensate. Due to the risk of nitrogen narcosis outside chamber staff should continue to make clinical decisions about patient care. Keywords: Nitrogen Narcosis, Hyperbaric Research, Psychology, Nursing Introduction to oxygen. The inside nurse attendant breathes air during either treatment other than during the final stages of Hyperbaric nursing is a specialty involved in the care decompression when they breathe oxygen. It follows that of patients receiving hyperbaric oxygen treatment. there is a widely perceived risk of nitrogen narcosis for Nurses, from a wide background of experience including the inside nurse. Consequently the outside staff make all emergency and critical care, complete training in the patient care decisions and the inside nurse performs hyperbaric and diving medicine. Hyperbaric nursing the skills at the request of the outside staff. However, the courses include both theoretical knowledge and practical actual degree of impairment in inside nurses has not been skills to equip nurses for working in the hyperbaric quantified. While much research has been done on environment. The nurses must be medically fit to “dive” SCUBA divers, mostly in deep diving (Biersner et al ., and perform training dives during their courses including 1978; Whitaker and Findley, 1977) in water and in dry a compression to 300 kilopascals (kPa). chambers, (Petri, 2003; Gallway et al ., 1991) no studies SCUBA divers with decompression illness are treated have investigated the effect of nitrogen narcosis on in hyperbaric chambers using standardized treatment hyperbaric chamber nurses. tables. Two initial treatment tables are commonly used at Nitrogen narcosis was made famous in the Self The Townsville Hospital Hyperbaric Medicine Unit. The Contained Underwater Breathing Apparatus (SCUBA) Royal Navy 62 (RN 62) treatment table prescribes diving community by Jacques Cousteau who called it compression to 180 kPa and the diver breathes oxygen. “l’ivresse des grandes profondeurs” or rapture of the The Comex 30 treatment table prescribes compression to great depths. Cousteau and Dumas (1958) It was 300 kPa and the diver breathes heliox (50% helium and correctly associated with the narcotic effects of nitrogen 50% oxygen) until 180 kPa where they are changed over breathed under pressure by Behnke et al . (1935), but its © 2014 Denise F. Blake, Derelle A. Young and Lawrence H. Brown. This open access article is distributed under a Creative Commons Attribution (CC-BY) 3.0 license. Denise F. Blake et al . / International Journal of Research in Nursing 2014, 5 (2): 44.51 DOI: 10.3844/ijrnsp.2014.44.51 precise mechanism of action still remains controversial. time to complete TMT A and an increased number of Experimental evidence supports the importance of errors. As no formal assessment of susceptibility to hypercapnia in divers but variations in alveolar CO2 nitrogen narcosis is performed during hyperbaric tensions seems to have little effect on the magnitude of nursing courses, the aim of this study was to quantify the nitrogen component in compressed air narcosis. the effects of nitrogen narcosis on both experienced and Bennett and Rostain (2003). The traditional view was that novice hyperbaric chamber nurses during a nitrogen was an inert gas, highly soluble in lipids and not compression to 180 and 300 kPa. involved in biochemical processes. However, more recent work has found that nitrogen acts on nerve cell membranes Methods interfering with impulse conduction (production, release and uptake of several neurotransmitters) most likely at the Participants synapses (Rostain et al ., 2011). Ethical approval was obtained from the Townsville The signs and symptoms of nitrogen narcosis have Health Service District Human Research Ethics been described as similar to those of alcohol Committee. (HREC/09/QTHS/2) Twenty eight subjects intoxication: Stimulation, excitement, euphoria and participated in the study. Relevant demographic data slowing of mental activity with delayed response to including alcohol consumption, body mass index, scuba stimuli. Early investigations demonstrated that at a depth diving experience and age were gathered from the of 30 metres of sea water (msw) (300 kPa) there is subjects’ diving medical examination record. The impairment of memory, concentration, calculations, intervention group consisted of sixteen hyperbaric powers of association and fine motor functions and also nursing candidates and five experienced hyperbaric a tendency to fixate on ideas. Behnke et al . (1935) nurses. This group was pressurized to 300 kPa as a routine Intellectual functions are generally more severely affected part of the hyperbaric nursing course. The non-pressurized than manual dexterity. Increased concentration can reference group consisted of seven experienced hyperbaric ameliorate these effects. The effects of nitrogen narcosis staff currently working in the hyperbaric medicine unit. are variable, with some divers being more susceptible than All participants who were pressurized had a current others. It may be potentiated by emotional instability, Australian Standard 4774.2 2002 dive medical. Written alcohol use, fatigue, hard work, apprehension and anxiety. informed consent was obtained. Frequent exposure to compressed air may afford some adaptation (Bennett and Rostain, 2003). Materials Various subjective feeling scales, physiological measurements and cognitive function tests have been The hyperbaric chamber used was the triple lock used to assess for nitrogen narcosis. Subjective feeling rectangular unit located at The Townsville Hospital, scales have attempted to equate the feelings of nitrogen Townsville, Queensland. The pressurizations were narcosis with that of alcohol intoxication (Monteiro et al ., undertaken in the inner lock, which has a working 1996; Hobbs, 2008) or delineate the effects of anxiety or pressure of 500 kPa and is used when completing an RN other emotional factors on the onset of nitrogen narcosis. 62 or Comex 30 treatment table. A certified hyperbaric Biersner et al . (1978); Gallway et al ., 1991; Davis et al ., technician operated the chamber for all pressurizations. 1972; Rogers and Moeller, 1989; Hamilton et al ., 1995) The TMT A was used as an objective measurement Studies using physiological measurements have of mental impairment during the pressurization. TMT A included heart rate and blood pressure (Biersner, 1987), is easy to perform, requires no objects that cannot be compressed and does not require an extensive amount of balance (Rogers and Moeller, 1989), EEG changes time to complete. Thus using TMT A does not influence (Pastena et al ., 2005) and critical flicker fusion the bottom time of the practice dive and does not require frequency. Balestra et al . (2012) Many different cognitive adjustment to the decompression schedule. TMT A was tests have been used in the research of nitrogen narcosis and initially developed as a test in the (AITB, 1944) and was no clear ideal test for quantifying nitrogen narcosis has yet incorporated into the Halstead-Reitan battery group of been identified. The cognitive function tests that have been tests in 1958. This test has been used to assess the used to measure nitrogen narcosis can be categorized into general intellectual ability of USA Army recruits (AITB, four behavioural endpoints: Reaction time, mental 1944) and to detect cognitive ability in aging drivers arithmetic, memory and manual dexterity. The specific test (Stutts et al ., 1998), dementia